A NetScope will get a default nettype from a parent.
A NetScope will get a default nettype from a parent.

The default nettype was not always being set. This patch
modifies the NetScope constructor to get the default
nettype from a parent if it exists. It is set to NONE if
a parent does not exist.

CastMi/iverilog,themperek/iverilog,CastMi/iverilog,themperek/iverilog,CastMi/iverilog,themperek/iverilog